Chemical pump for oil wells



July 16, 1963 c. R. BERKLEY 3,097,605

CHEMICAL PUMP FOR OIL WELLs Filed April 10, 1962 2 Sheets-Sheet 1 ll/l.Ill/l/I/ll/ I 16. INVENTOR.

C/YAQLES R. JERKLEY BY 5 2 Sheets-Sheet 2 I NVEN TOR.

ATTORNEY July 16, 1963 c. R. BERKLEY CHEMICAL PUMP FOR 01:. WELLS FiledApril 10, 1962 CHARZIFS R. JERALEY 3,097,605 Patented July 16, 1963sylvania Filed Apr. 10, 1962, Ser. No. 186,406 Claims. (Cl. 103-6) Thisinvention relates to a pump, and more particularly to a pump forinjecting liquid chemicals into the flow lines from a well.

Frequently, it is desirable to inject a liquid chemical treating agentinto the stream of fluids flowing through the flow line from a well. Oneor more objectionable conditions in the flow line may be alleviated bythe injected chemical. For example, the fluid produced by the well maybe corrosive. It is then desirable to inject a corrosion inhibitor intothe stream to prevent excessive corrosion of the flow line. In otherinstances, the well may produce a paraflinic oil which tends to depositparaffin on the wall of the flow line. It is then desirable to injectinto the flow line a fluid which will prevent the accumulation ofparalfin deposits on the flow line wall.

A number of different arrangements of pumps in combination with wellhead structures has been suggested to accomplish the desired object ofpumping a liquid into the flow line of a well at a controlled rate. Onecommonly used arrangement is to provide a separate drive for thechemical pump. Another arrangement uses a mechanical linkage driven bythe walking beam of the well pumping unit to drive the chemical pump.Although the apparatus driven by the walking beam has an importantadvantage in cost over the units having separate drives, it hasheretofore not been as readily installed at the well. The well pumpingunits of different manufacturers vary widely in their design, and eventhe pumping units of a single manufacturer dilfer widely in size,depending upon the rate of production of a particular well. Because ofthe large number of different types and sizes of pumping units anddifferent arrangements of apparatus at the well head, the chemical pumpsdriven from the walking beam have required a substantial amount offabrication at the well head.

The many different problems encountered in the flow lines of wellsrequire different chemicals for their solution; hence, there is a widevariation in the properties of chemicals injected into flow lines fromdifferent wells. Some of the chemicals are solvents of very lowviscosity, while others are highly viscous compositions. Moreover,because of the wide variation in rates of flow through the flow lines ofwells as well as the necessity of injecting chemicals at rates designedto produce different concentrations in the flow line liquids, widelatitude in adjustment of the flow rate of the chemical is essential.Particularly when the chemical treating agent is an expensive reagentinjected into the flow line at low rates, it is necessary to provide avery fine adjustment of the rate of discharge of the chemicals from thechemical pump as well as an adjustment over a wide range of flow rates.

This invention resides in a novel chemical pump for the injection ofliquid chemical treating agents into the flow line of wells throughwhich flows a stream of well fluids produced by a reciprocating pumpwithin the well. In the apparatus of this invention, a striker platemounted at the well head on the polish rod driving the well pump engagessuitable linkage to drive a plunger in the chemical pump downwardly in apump cylinder to discharge the chemical from the lower end of the pump.After initial installation of the striker plate on the polish rod, thelength of stroke of the chemical pump can be regulated by adjustment ofthe length of the plunger. A metering valve at the inlet of the chemicalpump provides further control of the rate of discharge of liquids fromthe chemical pump.

In the drawings:

FIGURE I is a diagrammatic view, partially in vertical section, of thepump of this invention assembled in position for operation;

FIGURE 2 is a vertical sectional view of the pump showing the plungerstructure and mechanism for returning the plunger to an upper position;

FIGURE 3 is a vertical sectional view of a metering valve provided atthe inlet of the pump; and

FIGURE 4 is a diagrammatic view showing a modified embodiment of thisinvention installed on a flow line of a well.

Referring to FIGURE 1, a well indicated generally by reference numeral10 is illustrated with a polish rod 12 extending upwardly through apacking gland 14 for connection to a walking beam 16 of a pumping unitin accordance with conventional practice. The walking beam is driven bythe usual means such as a pitman drive, not shown in the drawings.Extending from the well is a flow line 18 for the delivery of wellfluids to suitable storage, not shown.

Positioned adjacent the well 10 is a storage tank 20 which is shownresting on a platform around the well. Within the storage tank 20 is achemical pump, indicated generally by reference numeral 22. The chemicalpump 22 is shown with a nipple 24 connecting the inlet port, not shownin FIGURE 1, of the pump with a metering valve 26. Extending upwardlyfrom the metering valve 26 is a metering rod 28 which forms an extensionof valve stem 30 of the metering valve. Metering rod 28 is provided witha threaded section 32 near its upper end having a lock nut 34 movablethereon and adapted to engage a plate on the cover 36 of the storagetank 20 to lock the metering rod in position.

Connected to the lower end of the pump 22 is a discharge line 38 whichis shown extending upwardly through the storage tank 20 and out of theupper end thereon. A pressure gauge 40 may be connected in the dischargeline 38 for indication of the pressure developed by the chemical pump. Ableed valve 42 is connected to the side outlet of a T 44 in thedischarge line. The dis charge line 38 continues past the T 44 and isconnected to the well flow line 18. A valve 46 is installed in thedischarge line 38 between the T 44 and the flow line 18.

Referring to FIGURE 2, the chemical pump 22 has a pump cylinder 48having a bore 50 extending vertically therethrough intersected by aninlet port 52. Extending upwardly from the pump cylinder 48 is a tubularhousing 54 which is internally threaded at its upper end to receive abushing 56. At the lower end of the pump cylinder 48 is a check valve 58having a central opening therethrough communicating with the bore 50.Within the check valve body 58 is a ball valve 60 urged upwardly againsta valve seat 64 by a compressed helical spring 62. The check valveallows downward flow from the llaore 50 into an L 66 which forms part ofthe discharge inc 38.

Fitting slidably within the bore 50 of the pump cylinder 48 is a pumpplunger 68 which extends upwardly out of the pump cylinder 48 into thehousing 54. Leakage around plunger 68 is prevented by an O-ring 69 in arecess in the upper end of the bore 50. An extension tube 70 threaded tothe upper end of the pump plunger 68 extends upwardly through thebushing 56. Surround ing the plunger 68 and extension tube 70 within thehousing 54 is a helical spring 72 which is compressed between the upperend of the pump cylinder 48 and a collar 75 secured at a desiredposition on the extension tubing 70 by means of a set screw 76. A sleeve74 surrounding extension 70 rests on collar 75. Secured in the upper endof bushing 56 is a stop collar 78 which is adapted to engage the upperend of the sleeve 74 and thereby limit upward movement of the plunger68. A plunger head 80 threaded to the upper end of the extension tube 70can be locked in place by a lock nut 82.

Adjustment of the compression of the spring 72 is accomplished bychanging the position of collar 75. If a change in the extent of upwardmovement of the plunger 68 is desired, a sleeve of suitable length issubstituted for sleeve 74 to compensate for the change in position ofcollar 75. In general, the compression of spring 72 and the extent ofupward movement of the plunger are greater for chemical liquids of highviscosity.

Referring to FIG. 3, the metering valve 26 is illustrated having a sideoutlet 84 threaded for connection to the nipple 24. Valve stem 30extends downwardly through a packing gland 86 and is provided at itslower end with a conical surface 88 adapted to engage a valve seat 90 toprovide a needle valve permitting fine control of the rate of flow intothe chemical pump. Flow into the metering valve is through an inletscreen 92 connected to an L 94 having an opening therethroughcommunicating with a vertical passage 96 in the metering valve to thevalve seat 90.

As shown in FIGURE 1, on the top of the cover 36 of the storage tank isa pair of brackets 98 with a rotatable shaft 100 extending between them.Secured to the shaft 100 is a lever arm 102 made up of a tubular memberconnected to the shaft into which an extension 104 is slidable. Theposition of extension 104 can be adjusted by means of a set screw 106.At the outer end of the extension 104 is a collar 108 threaded toreceive a threaded striker pin 110. A lock nut 112 on the striker pincan be tightened against the collar 108 to secure the striker pin in thedesired position.

The lever arm 102 extends directly above the plunger head 80 to drivethe pump in the manner hereinafter described. For convenience inassembly, the apparatus positioned within the storage tank 20 isassembled on a plate 114, which in turn is secured to the cover 36 ofthe storage tank. The pump 22 extends upwardly through a nut 116 securedon the plate 114 and is locked at the desired elevation by means of aset screw 120 which engages housing 54.

In the operation of the chemical pump of this invention, the storagetank 20 is set in place, preferably as close as possible to the wellhead. The head 80 of the pump plunger is moved to an upper position onthe plunger and the lever arm pressed downwardly to move the lower endof the pump plunger 68 to the bottom of the bore 50. With the pumpplunger held in this lower position, the walking beam 16 is moved to itslowest position to locate the polish rod 12 at its lowest position. Astriker plate 122 is then fastened on the polish rod just above thestriker pin 110. The striker pin 110 is then raised in collar 108 untilit just touches the lower surface of the striker plate 122 and is lockedin that position. It is a common practice to rotate the polish rod andsucker rod of a pump during operation of the well pump. For this reason,it is preferred that the striker plate 122 be a circular disc.

The walking beam 16 is then raised to raise the striker plate 122 out ofengagement with the striker pin 110. The compressed spring 72 within thehousing 54 raises the pump plunger 68 to the uppermost positiondetermined by the sleeve 74. The head 80 of the plunger is then adjusteddownwardly to shorten the effective length of the plunger and therebyfix the length of stroke of the pump plunger 68 below the inlet port,which in turn controls the amount of liquid discharged by each stroke ofthe plunger.

With valve 46 closed and valve 42 open, the well pumping unit is placedin operation. The striker plate 122 engages the striker pin 110 on eachstroke of the well pump and moves the lever arm 102 downward. Down wardmovement of lever arm 102 forces the pump plunger downwardly in the pumpto discharge liquid from the bore 50.

The rate of pumping is measured by observation of the rate of dischargethrough the bleeder valve 42. Major adjustments in the rate of flow aremade by adjustment of the eflective length of the pump plunger byadjustment of the position of plunger head on plunger extension 70.After the rate of discharge from the pump 22 is close to the desiredvalue, final adjustments are made by means of metering valve 26. Valve46 is then opened and valve 42 is closed. The metering valve isparticularly effective when the chemical to be injected into the flowline of the well is highly viscous. The metering valve also allowsaccurate adjustment of the rate of flow or complete shut oil of thechemical pump to be made while the well pumping unit continues inoperation. On the upward movement of the polish rod 12, the strikerplate 122 moves out of engagement with striker pin 110. Spring 72 movesthe pump plunger upwardly to a position with its lower end above theinlet port 52 in the pump cylinder 48. A weak spring 124 holds the leverarm 102 against the plunger head.

Referring to FIGURE 4 of the drawings, a modified arrangement isillustrated in which the storage tank 20 is mounted on an adjustablebase 126. The base 126 is supported directly on the flow line 18 of thewell.

The unique driving mechanism for the chemical pump described hereinpermits a single pump structure to be utilized with a wide variety ofsizes and types of well pumping units. The long vertical span of thepolish rod over which the striker plate 122 may be attached provides amaximum flexibility for the installation of the chemical pump assembly.Driving of the chemical pump directly from the polish rod is alsoadvantageous in providing a compact unit immediately adjacent the wellhead, and thereby greatly decreases the chances of damage to theassembled apparatus. The ease of adaptation of the chemical pump fordifferent types of units allows it to be installed by ordinary oil fieldworkers.

The combination of the metering valve and the plunger of adjustablelength provides a wide range of adjustment of the capacity of the pumpwhile permitting very accurate control of the flow rate even when therate of injection of the chemical into the llow line is extremely low.With this arrangement, a single chemical pump structure can be used forpumping chemicals of widely dillerent characteristics, as well as forpumping the chemicals at widely different rates. The metering valve isalso highly effective in permitting accurate adjustment of the pumpingrate while the well pumping unit remains in operation. Accurateadjustment of the rate of discharge is facilitated because the change inthe position of the plunger head 80 on the plunger extension 70 is thesame as the change in the effective stroke of the plunger; hence, theextent of adjustment can be observed directly.

1 claim:

1. Apparatus for the injection of a liquid into the flow line of an oilwell equipped with a reciprocating pump driven by a polish rod extendingupwardly from the well head comprising a storage tank for the liquid, apump cylinder positioned in said storage tank, said pump cylinder havinga bore extending vertically therethrough, an inlet port extendingthrough the cylinder and intersecting the bore above the lower endthereof, conduit means from the lower end of the cylinder to the flowline of the pump for delivery of liquids from the pump into the flowline, a check valve in the conduit means, a plunger movable in the boreof the cylinder from a position above the inlet port to a position belowthe inlet port, a striker plate mounted on the polish rod, an armunattached to the striker plate extending to a position below thestriker plate whereby said arm is engaged and moved downwardly by thestriker plate on downward movement of the striker plate, said armextending over the upper end of the plunger and adapted to move theplunger downwardly on downward movement of the polish rod to itslowermost position to drive the plunger downwardly in the bore of thepump, means for adjusting the length of the plunger to control thedistance below the inlet valve traveled by the plunger, and resilientmeans engaging the plunger to urge said plunger upwardly against thearm.

2. Apparatus for the injection of a liquid into the flow line of an oilwell equipped with a reciprocating pump driven by a polish rod extendingupwardly from the well head comprising a storage tank, a pump cylinderpositioned in said storage tank, said pump cylinder having a boreextending vertically therethrough, an inlet port extending through thecylinder and intersecting the bore above the lower end thereof, ametering valve connected in that port, conduit means from the lower endof the cylinder to the flow line of the well for delivery of liquidsfrom the pump into the flow line, a check valve in the conduit means, aplunger movable in the bore of the cylinder from a position above theinlet port to a position below the inlet port, a striker plate mountedon the polish rod, an arm unattached to the striker plate extendingbelow the striker plate for engagement by the striker plate on downwardmovement thereof, said arm extending over the plunger and adapted tomove the plunger downwardly on downward movement of the polish rod todrive the plunger downwardly in the bore of the pump, means foradjusting the length of the plunger to control the distance below theinlet port traveled by the plunger, and resilient means engaging theplunger to urge said plunger upwardly against the arm and return theplunger to a position above the inlet port.

3. Apparatus for the injection of liquid into the flow line of an oilwell equipped with a reciprocating pump driven by a polish rod,comprising a storage tank, a pump cylinder having a bore extendingvertically therethrough, an inlet port extending through the cylinderand intersecting the bore above the lower end thereof, conduit meansfrom the lower end of the cylinder to the flow line of the well fordelivery of liquids from the pump cylinder into said fiow line, a checkvalve in the conduit means, a plunger movable in the bore of thecylinder between a position above the inlet port and a position belowthe inlet port, a tubular housing extending upwardly from the pumpcylinder, said pump plunger extending upwardly through the housing to aposition above the upper end thereof, a sleeve mounted on the pumpplunger above the pump cylinder, a helical spring compressed between thepump cylinder and the sleeve to urge the pump plunger upwardly, meansextending inwardly from the housing above the sleeve to engage thesleeve and limit upward fit movement of the plunger, a striker platemounted on the polish rod, an arm pivotally mounted on the storage tankextending directly above the upper end of the plunger, said arm beingunattached to the striker plate and extending to a position below thestriker plate whereby downward movement of the striker plate to itslowermost position moves the arm against the upper end of the plunger todrive the plunger downwardly, and means for adjusting the length of theplunger to control the distance below the inlet port traveled by theplunger.

4. Apparatus as set forth in claim 4 in which an inlet line extends fromthe inlet port for delivery of the liquid to the inlet port, and ametering valve connected in the inlet line.

5. A chemical pump for the injection of liquid into the flow line of anoil well equipped with a reciprocating pump driven by a polish rodconnected to a walking beam, comprising a storage tank, a pump cylinderhaving a bore extending vertically therethrough, an inlet port extendingthrough the cylinder and intersecting the bore above the lower endthereof, conduit means from the lower end of the cylinder to the fiowline of the well for delivery of liquids from the pump cylinder intosaid flow line, a check valve in the conduit means, a plunger movable inthe bore of the cylinder between a position above the inlet port and aposition below the inlet port, a tubular housing extending upwardly fromthe pump cylinder, said pump plunger extending upwardly through thehousing to a position above the upper end thereof, a sleeve secured onthe pump plunger above the pump cylinder, a helical spring compressedbetween the pump cylinder and the sleeve to urge the pump plungerupwardly, means extending inwardly from the housing above the sleeve toengage the sleeve and limit upward movement of the plunger, a strikerplate mounted on the polish rod, an arm pivotally mounted on the storagetank extending directly above the upper end of the plunger, said armbeing unattached to the striker plate and extending to a position belowthe striker plate whereby downward movement of the striker plate engagesthe arm to drive the plunger downwardly on movement of the striker plateto its lowermost position, means for adjusting the length of the plungerto control the distance below the inlet port traveled by the plunger,and means for adjusting the position of the sleeve on the plunger forcontrol of the compression of the helical spring.

References Cited in the tile of this patent UNITED STATES PATENTS1,764,545 Brown June 17, 1930 2,047,414 Henry et al July 14, 19362,063,863 Zimmerman et al Dec. 8, 1936 2,524,963 Davis Oct. 10, 1950

1. APPRATUS FOR THE INJECTION OF A LIQUID INTO THE FLOW LINE OF AN OILWELL EQUIPPED WITH A RECIPROCATING PUMP DRIVEN BY A POLISH ROD EXTENDINGUPWARDLY FROM THE WELL HEAD COMPRISING A STORAGE TANK FOR THE LIQUID, APUMP CYLINDER POSITIONED IN SAID STORAGE TANK, SAID PUMP CYLINGER HAVINGA BORE EXTENDING VERTICALLY THERETHROUGH, AN INLET PORT EXTENDINGTHROUGH THE CYLINDER AND INTERSECTING THE BORE ABOVE THE LOWER ENDTHEREOF, CONDUIT MEANS FROM THE LOWER END OF THE CYLINDER TO THE FLOWLINE OF THE PUMP FOR DELIVERY OF LIQUIDS FROM THE PUMP INTO THE FLOWLINE, A CHECK VALVE IN THE CONDUIT MEANS, A PLUNGER MOVABLE IN THE BOREOF THE CYLINDER FROM A POSITION ABOVE THE INLET PORT TO A POSITION BELOWTHE INLET PORT, A STRIKER PLATE MOUNTED ON THE POLISH ROD, AN ARMUNATTACHED TO THE STRIKER PLATE EXTENDING TO A POSITION BELOW THESTRIKER PLATE WHEREBY SAID ARM IS ENGAGED AND MOVED DOWNWARDLY BY THESTRIKER PLATE ON DOWNWARD MOVEMENT OF THE STRIKER PLATE, SAID ARMEXTENDING OVER THE UPPER END OF THE PLUNGER AND ADAPTED TO MOVE THEPLUNGER DOWNWARLDY ON DOWNWARD MOVEMENT OF THE POLISH ROD TO ITSLOWERMOST POSITION TO DRIVE THE PLUNGER DOWNWARDLY IN THE BORE OF THEPUMP, MEANS FOR ADJUSTING THE LENGTH OF THE PLUNGER TO CONTROL THEDISTANCE BELOW THE INLET VALVE TRAVELED BY THE PLUNGER, AND RESILIENTMEANS ENGAGING THE PLUNGER TO URGE SAID PLUNGER UPWARDLY AGAINST THEARM.